Abortion rights supporters demonstrate outside the Capitol auditorium in Austin, Texas, as Gov. Rick Perry (R) signs sweeping new abortion restrictions earlier this month. The South Central region of the US has seen significant growth in opposition to abortion since 1995, according to a new Pew poll.

Washington — Opinion on abortion in the United States has held mostly steady for the past two decades, but regional differences are widening, according to the Pew Research Center.

That growing regional divide comes as many of the states in conservative regions add new laws regulating abortion doctors and clinics. In particular, the South Central region – Alabama, Arkansas, Kentucky, Louisiana, Mississippi, Oklahoma, Tennessee, and Texas – has seen significant growth in opposition to abortion since 1995, Pew found.

“The most important trend in this report is that the balance has flipped” in the South Central part of the country, says Carroll Doherty, associate director of the Pew Research Center. “You always saw less support for legal abortion in South Central, but since the '90s, it’s flipped from modestly in favor to 12 points against.”

In that region, 40 percent of adults surveyed in 2012 and 2013 said abortion should be legal in all or most cases, versus 52 percent who said it should be illegal in all or most cases. In 1995 and 1996, 52 percent of Southerners supported abortion rights in all or most cases and 45 percent said abortion should be illegal in all or most cases.

Exactly why that shift has occurred is open to conjecture. Some analysts point to technology, such as growing use of sonograms early in pregnancy, as one explanation. The South has long been known for its high levels of religiosity, particularly evangelical Christianity.

The growing polarization of views on abortion also reflects the polarization of politics in the US between red and blue states, and in Congress.

A national Pew survey conducted July 17-21 found that 54 percent of Americans say abortion should be legal in all or most cases, and 40 percent say it should be illegal in all or most cases. In 1995-96, the figures were 60 percent favoring legal abortion and 38 percent opposing abortion all or most of the time.